October 2 -- In the first randomized trial of its kind, Tadalafil, a drug typically prescribed for erectile dysfunction in men, has been proven to increase the sexual function of prostate cancer survivors, according to a study released today from the International Journal of Radiation Oncology*Biology*Physics, the official journal of ASTRO.

Prostate cancer is the most commonly diagnosed cancer in men, with an estimated 235,000 Americans expected to be diagnosed with it this year. In its early stage, prostate cancer can be treated with surgery and radiation therapy or a combination of the two. With more advanced cancer, treatment options can vary.

The walnut-sized prostate is located near the tubes that carry urine and semen. After treatment, some patients report trouble achieving an erection sufficient for sexual activity, also called erectile dysfunction or ED. In this study, doctors wanted to test whether the drug Tadalafil, which sells under the brand name Cialis, would help prostate cancer survivors with ED who were treated with three-dimensional conformal radiation therapy (3D-CRT). This is the first randomized, placebo-controlled, double-blind trial to examine Tadalafil's lasting effect in treating patients who have ED after radiation therapy for prostate cancer.

Nearly 360 patients were treated for prostate cancer at the Erasmus MC-Daniel den Hoed Cancer Center in The Netherlands between 1998 and 2002. Among them, 60 patients complaining of erectile dysfunction after radiation therapy were included. Patients were eligible if they were treated with 3D-CRT at least 12 months before the study entry, agreed not to use any other treatment for ED and agreed to make at least one sexual intercourse attempt every week during the 12-week trial. Patients were given an initial 4-week course of no treatment at all; however, patients had to attempt sexual activity at least once a week in this 4-week period.

Patients were given 20mg of Tadalafil or a placebo for 6 weeks. Patients were allowed to take the drug or placebo at-will with no restrictions on food or alcohol, but no more than once per day. The men were instructed that the drug would be effective for as long as 36 hours after dosing. After the first 6-week period of the trial, participants were moved onto alternative treatment; patients who were given placebo were switched to Tadalafil and vice versa.

Doctors found that successful intercourse was reported in 48 percent of the survivors who took Tadalafil versus the 9 percent of the men who were given placebo. There was also a reported improvement of the quality of erections in 67 percent of the patients versus only 20 percent of the placebo group.

"Fortunately, prostate cancer is a very curable disease with most patients living at least five years after diagnosis. Now that we've proven we can beat the disease, it's imperative that we work to help maintain the quality of life for the men who survive it, including preserving their sexual function," said Luca Incrocci, M.D., Ph.D., lead author of the study. Dr. Incrocci is a radiation oncologist at the Erasmus MC-Daniel den Hoed Cancer Center in The Netherlands. "This study proves that the drug Cialis is effective in helping men maintain their sexual health."

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For more information on prostate cancer treatment options, please visit www.rtanswers.org. To arrange an interview with Dr. Incrocci or for a copy of the study, please contact Julie Moore.

ASTRO is the largest radiation oncology society in the world, with more than 8,500 members who specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, biology and physics, the Society is dedicated to the advancement of the practice of radiation oncology by promoting excellence in patient care, providing opportunities for educational and professional development, promoting research and disseminating research results and representing radiation oncology in a rapidly evolving socioeconomic healthcare environment.

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